compiler throw related to rulesDST

[buffetboy2001]

Thanks for the handy library and the Word Matrix Clock project. Looks like I uncovered a bug in v1.1.X of your code; it throws when Arduino IDE v1.8.13 builds. I have not spent enough time with it to provide a resolution. The compiler fails due to an "undefined reference to rulesDST". Clearly it is declared in the header on line 5. So, not sure right now what the problem might be.

DST_RTC/DST_RTC.h

Line 5 in e956694

extern const char rulesDST[];

This occurs when building on Windows and Mac. On both, if I roll back the library to v1.0.0, the code (Word Clock code) builds.